In vitro antibacterial properties and UV induced response from Staphylococcus epidermidis on Ag/Ti oxide thin films

  • Erik UnossonEmail author
  • Matthias Morgenstern
  • Håkan Engqvist
  • Ken Welch
Biomaterials Synthesis and Characterization Original Research
Part of the following topical collections:
  1. Biomaterials Synthesis and Characterization


Implanted materials are susceptible to bacterial colonization and biofilm formation, which can result in severe infection and lost implant function. UV induced photocatalytic disinfection on TiO2 and release of Ag+ ions are two promising strategies to combat such events, and can be combined for improved efficiency. In the current study, a combinatorial physical vapor deposition technique was utilized to construct a gradient coating between Ag and Ti oxide, and the coating was evaluated for antibacterial properties in darkness and under UV light against Staphylococcus epidermidis. The findings revealed a potent antibacterial effect in darkness due to Ag+ release, with near full elimination (97 %) of viable bacteria and visible cell lysis on Ag dominated surfaces. The photocatalytic activity, however, was demonstrated poor due to low TiO2 crystallinity, and UV light irradiation of the coating did not contribute to the antibacterial effect. On the contrary, bacterial viability was in several instances higher after UV illumination, proposing a UV induced SOS response from the bacteria that limited the reduction rate during Ag+ exposure. Such secondary effects should thus be considered in the development of multifunctional coatings that rely on UV activation.

Graphical Abstract


TiO2 Photocatalytic Activity Oxide Thin Film Plasma Electrolytic Oxidation Bacterial Viability 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This work was supported by the Swedish Foundation for Strategic Research (SSF), through the ProViking Project.


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Copyright information

© Springer Science+Business Media New York 2016

Authors and Affiliations

  • Erik Unosson
    • 1
    Email author
  • Matthias Morgenstern
    • 1
  • Håkan Engqvist
    • 1
  • Ken Welch
    • 2
  1. 1.Division of Applied Materials Science, Department of Engineering Sciences, The Ångström LaboratoryUppsala UniversityUppsalaSweden
  2. 2.Division of Nanotechnology and Functional Materials, Department of Engineering Sciences, The Ångström LaboratoryUppsala UniversityUppsalaSweden

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